1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2020 The FreeBSD Foundation 5 * 6 * This software was developed by Tiger Gao under sponsorship from 7 * the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions are 11 * met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <gelf.h> 32 #include <libelf.h> 33 34 #include "_libelf.h" 35 36 void * 37 _libelf_getchdr(Elf_Scn *s, int ec) 38 { 39 Elf *e; 40 void *sh; 41 Elf32_Shdr *sh32; 42 Elf64_Shdr *sh64; 43 44 sh32 = NULL; 45 sh64 = NULL; 46 47 if (s == NULL || (e = s->s_elf) == NULL || e->e_kind != ELF_K_ELF) { 48 LIBELF_SET_ERROR(ARGUMENT, 0); 49 return (NULL); 50 } 51 52 if (ec == ELFCLASSNONE) { 53 ec = e->e_class; 54 } else if (ec != e->e_class) { 55 LIBELF_SET_ERROR(CLASS, 0); 56 return (NULL); 57 } 58 59 if ((sh = _libelf_getshdr(s, ec)) == NULL) { 60 LIBELF_SET_ERROR(HEADER, 0); 61 return (NULL); 62 } 63 64 if (ec == ELFCLASS32) { 65 sh32 = (Elf32_Shdr *)sh; 66 if ((sh32->sh_flags & SHF_ALLOC) != 0) { 67 LIBELF_SET_ERROR(INVALID_SECTION_FLAGS, 0); 68 return (NULL); 69 } 70 71 if (sh32->sh_type == SHT_NULL || sh32->sh_type == SHT_NOBITS) { 72 LIBELF_SET_ERROR(INVALID_SECTION_TYPE, 0); 73 return (NULL); 74 } 75 76 if ((sh32->sh_flags & SHF_COMPRESSED) == 0) { 77 LIBELF_SET_ERROR(NOT_COMPRESSED, 0); 78 return (NULL); 79 } 80 } else { 81 sh64 = (Elf64_Shdr *)sh; 82 if ((sh64->sh_flags & SHF_ALLOC) != 0) { 83 LIBELF_SET_ERROR(INVALID_SECTION_FLAGS, 0); 84 return (NULL); 85 } 86 87 if (sh64->sh_type == SHT_NULL || sh64->sh_type == SHT_NOBITS) { 88 LIBELF_SET_ERROR(INVALID_SECTION_TYPE, 0); 89 return (NULL); 90 } 91 92 if ((sh64->sh_flags & SHF_COMPRESSED) == 0) { 93 LIBELF_SET_ERROR(NOT_COMPRESSED, 0); 94 return (NULL); 95 } 96 } 97 98 Elf_Data *d = elf_getdata(s, NULL); 99 100 if (!d) 101 return (NULL); 102 103 return ((void *)d->d_buf); 104 } 105